WASHINGTON (Reuters) - The United States plans to release 140 of the 660 prisoners at its Guantanamo Bay, Cuba, prison for suspects in the U.S.-declared war on terrorism, Time magazine reported on Sunday. Slated for release were "the easiest 20 percent" of detainees, a military official told the magazine. It did not identify its source, who said the military was waiting for "a politically propitious time to release them." A Pentagon spokesman was not immediately available for comment. No charges have been filed against any of the 660 prisoners at the U.S. Navy base in Cuba. Defense officials say many...